Abstract: This disclosure provides methods for treating a tumor in a subject comprising administering to the subject an anti-PD-1 antibody and an anti-CD30 antibody. In some embodiments, the tumor is derived from a lymphoma (e.g., a Hodgkin lymphoma or a non-Hodgkin lymphoma). In certain embodiments, the anti-CD30 antibody is an antibody-drug conjugate, e.g., brentuximab vedotin.